Earlier experiments have shown that a substantial fraction of mRNA molecules in Bacillus subtilis and related bacterial species carry polyadenylate sequences at their 3 feet-ends. Such sequences have long been recognized in mRNA of eukaryotic cells, but on account of the greater complexity of RNA metabolism in these organisms, their function has been difficult to define. We hope that the characterization of poly(A)-containing RNA in the simpler bacterial system may be more amenable to the elucidation of its function. The proposed experiments will involve the preparation and cloning of DNA sequences complementary to polyadenylated RNA and their use, for the isolation of specific poly(A)-RNA molecules. The structure, translatability, turnover rate, physiological and developmental regulation of different poly(A)-RNA species will be studied. In addition, we will address ourselves to the question whether the poly-adenylate sequences are directly transcribed from DNA or are added posttranscriptionally by specific enzymes. Specific genes which have already been cloned in other laboratories should also be analyzed for identification of poly(A)-RNA as the gene transcripts. This would permit the correlation of particular cellular function with poly(A)-RNA.